I. Field
The present disclosure relates generally to wireless communications and more specifically to control data transmissions.
II. Background
Wireless communication systems are widely deployed to provide various types of communication content such as, for example, voice, data, and so on. Typical wireless communication systems may be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, . . . ). Examples of such multiple-access systems may include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and the like. Additionally, the systems can conform to specifications such as third generation partnership project (3GPP), 3GPP long term evolution (LTE), ultra mobile broadband (UMB), etc.
Generally, wireless multiple-access communication systems may simultaneously support communication for multiple mobile devices. Each mobile device may communicate with one or more access points (e.g., base stations, femtocells, picocells, relay nodes, and/or the like) via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from access points to mobile devices, and the reverse link (or uplink) refers to the communication link from mobile devices to access points. Further, communications between mobile devices and access points may be established via single-input single-output (SISO) systems, multiple-input single-output (MISO) systems, multiple-input multiple-output (MIMO) systems, and so forth. In addition, mobile devices can communicate with other mobile devices (and/or access points with other access points) in peer-to-peer wireless network configurations.
Logical channels can be defined over a set of transmission resources (e.g., portions of frequency over time), such as control channels, data channels, etc. Transmit and receive antennas can be used to communicate data over the resources defined by the channels. For example, in 3GPP LTE, a physical downlink control channel (PDCCH) is provided to allow access points to communicate control data to the mobile devices regarding communications received over one or more data channels. Control data can relate to, for example, quality of transmissions received over a related uplink data channel, automatic repeat/request (ARQ) or other retransmission indicators, etc. Diversity schemes can be implemented for the channels as well, for example, to minimize interference thereover. In one example, spatial-frequency block coding (SFBC) and/or frequency switched transmit diversity (FSTD) can be utilized to provide PDCCH diversity depending on a number of transmit antennas.